Catheter with joinable lumens

ABSTRACT

A multiple lumen catheter having at least two lumens separate and independent from each other along at least a portion of their lengths, and that can be selectively joined together to change the separation distances between the lumens by way of a connecting means.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates generally to the field of cathetersfor use in applications that require blood, fluids, medicated solutions,and other solutions to be removed from and introduced into a person.More particularly, the present invention relates to catheters havingdual or multiple independent lumens in which a practitioner can controlthe distance of separation between the lumens at the distal end of thecatheter.

[0003] 2. Prior Art

[0004] Hemodialysis, one procedure that requires the introduction andremoval of blood from a patient, is a routine treatment for patientswith renal failure. When patients are placed on hemodialysis, suchpatients require the placement of a catheter into a large blood vesselthrough a subcutaneous tunnel. In conventional procedures including theSeldinger technique, the catheter is inserted into the patient's bloodvessel. This catheter, termed a hemodialysis catheter, is connected to ahemodialysis machine and is the vital connection between the patient andthe hemodialysis unit. Once the practitioner has properly inserted thehemodialysis catheter into the patient, reliable hemodialysis can beperformed for weeks to months using the placed catheter.

[0005] U.S. Pat. Nos. 6,190,349 and 5,947,953 to Ash et al. disclose amultiple catheter assembly and methods for inserting the same, in whichfirst and second catheters are connected by a splittable membrane. Thecatheter assemblies in Ash '349 and Ash '953 comprise at least twoindependent catheters that are splittable to a length not predeterminedby the catheter assembly. As the catheter assemblies in Ash '349 and Ash'953 are splittable as such, it may be possible to split or separate thecatheters from each other within the assembly substantially beyond adesired or desirable length, which in some cases can impair the functionof the catheter assembly. The thinness of the membrane initially holdingthe two lumens to each other makes this a likely possibility. Similarly,once the Ash '349 and Ash '953 lumens are split from each other, theycannot be reattached to each other.

[0006] U.S. Pat. No. 6,001,079 to Pourchez discloses a multilumencatheter comprising two lumens defined by a single wall for guiding afluid. The Pourchez '079 catheter is for the circulation of at least onefluid between a patient's body cavity or vessel and a fluid circulatingmeans. Although the Pourchez '079 catheter has separated catheter lumentips, the distance between the lumen tips is predetermined and is notadjustable. Further, the unseparated portion of the lumens of thePourchez '079 catheter are joined together and are not independent asthey share a common wall. As the Pourchez '079 catheter has a setseparation distance between the two lumens, which cannot be changed, thePourchez '079 catheter may not be useful for a wide variety of sizes ofpatients. there is a need for an improved catheter, more particularly ahemodialysis catheter with improved stability and performance. Further,there is a need for a catheter that can remain within a paitent withless chest discomfort. It is to this and other needs that the presentinvention is directed.

BRIEF SUMMARY OF THE INVENTION

[0007] The present invention includes a catheter with multiple joinablelumens such that the distance between the two lumens at a distal end ofthe catheter can be varied. While the invention is described herein inconjunction with the preferred and illustrative embodiments, it will beunderstood that the invention is not limited to these embodiments.

[0008] The catheter of the present invention is intended for use inapplications in which bodily fluids, medicated solutions, and othersolutions are introduced into and/or removed from the body. For example,in the case of hemodialysis treatment, one embodiment of the inventionis useful for the removal of blood from a patient for purification andfor reintroducing the blood into the patient after purification throughthe same blood vessel. In such applications, the catheter can be used inmany blood vessels including the femoral blood vessels, subdlavian bloodvessels or other blood vessels.

[0009] The catheter of the present invention has two ends that havedistinctive functions. More particularly, a distal end of the catheteris adapted to extend within the patient and a proximal end, opposite thedistal end, of the catheter is adapted to remain outside the patient'sbody for cooperating with a means for treating or purifying the fluidsdrawn from the patient.

[0010] In one embodiment, the catheter has at least two lumens that areapproximately parallel to one another. The at least two lumens are longenough to extend though the subcutaneous tunnel from the exit site tothe catheterized blood vessel. The at least two lumens are formed fromtwo independent tubular structures. Each tubular structure has arelatively constant wall thickness and flow cross-section across itslength and is used for facilitating simultaneous opposing fluid flowbetween the patient and an exterior unit, for example, a hemodialysisunit. Further, as the catheter can be within the patient for asignificant period of time, each lumen is sufficiently flexible to avoiddiscomfort, trauma, or stenosis to the patient.

[0011] The at least two lumens of the catheter are joinable at sectionsalong the walls of the at least two lumens towards the distal end of thecatheter. These sections may be pre-selected or non-preselecteddistances. In one embodiment, the lumens are joinable at pre-selectedpositions on generally opposite flat facing surfaces of each of the atleast two lumens. As more sections of the lumens are joined, thedistance between the distal tips of the lumens is decreased. In manycases, the joining of sections of the at least two lumens allows thepractitioner to control the distance between the tips at the distal endof the catheter, which can be used to maximize the fluid flow and thecomfort to the patient.

[0012] The means for joining the lumens of the catheter can be numerous.An illustrative example includes a joining means such as a series ofinterlocking junctions, in which the elements of each locking junctioncooperate with each other to lock the at least two lumens together.Another illustrative example includes the use of an adhesive placedalong the facing walls of the lumens so that the at least two lumens canbe joined by pressing the facing walls of the respective lumenstogether.

[0013] The joinable tip configuration of the catheter allows the atleast two lumens to be spaced apart from one another a selected distancewithout compromising the structure and structural integrity of each ofthe at least two lumens. This ability to change the spacing between theat least two lumens can allow the practitioner to adjust the catheter tofit different patients without affecting the function of the catheter.In a hemodialysis application, this spacing can help to prevent mixingof the cleansed blood, which returns through one of the at least twolumens, and the blood being removed from the blood vessel, which leavesthrough another one of the at least two lumens.

[0014] In operation and use, the catheter can be used for the removal offluid to be purified from the patient and/or subsequently for thereintroduction of purified fluid into patient. Initially, the at leasttwo lumens are supplied separated from each other along the length ofthe lumens an amount equal to or preferably greater than the maximumdistance recommended for the specific procedure. Before, after or duringthe installation of the catheter, the practitioner then can join the atleast two lumens together along the facing walls of the at least twolumens using the joinable means to reduce the separation distance to thedesired or required distance. In one example, after the joining of theat least two lumens as necessary, the catheter can be installed into apatient by ordinary medical techniques, after which the catheter canperform its function. In another example, such as in the case ofhemodialysis, after the catheter has been joined and inserted throughthe patient's skin into the appropriate blood vessel (by techniques suchas the Seldinger technique), blood is channeled out of the patientthrough one lumen of the at least two lumens to a purification machineand after purification the blood is channeled back into the patientthrough another of the at least two lumens.

[0015] Although embodiments of the present invention are generallydisclosed in the context of hemodialysis catheters, it is understoodthat such embodiments can be applied to other catheters that are usedfor procedures that require that fluid, blood, medicated solution, orother solutions be removed and introduced into a patient. Suchprocedures include, but are not limited to, hemodialysis, perfusion,chemotherapy, and plasmapheresis.

[0016] These features and advantages of the present invention and thecomplementary method for installation and use of the invention willbecome more apparent to those of ordinary skill in the art when thefollowing detailed description of the preferred embodiments is read inconjunction with the appended figures, in which like reference numeralsrepresent like components throughout the various figures.

BRIEF DESCRIPTION OF THE FIGURES

[0017]FIG. 1 is a perspective view of one illustrative embodiment of thepresent invention.

[0018]FIG. 2 is a perspective view of the distal end of the embodimentshown in FIG.1.

[0019]FIG. 3 is a perspective view of the distal end of a secondillustrative embodiment of the present invention.

[0020]FIG. 4 is perspective view of the distal end of a thirdillustrative embodiment of the present invention.

[0021]FIG. 5 is a cross section along line 5-5′ of the embodiment shownin FIG. 1.

[0022]FIG. 6 is a sectional view of a body with the embodiment shown inFIG. 1 placed therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Illustrative embodiments of the present invention includemultiple lumen catheters 10 that have at least two joinable lumens 12,14 such that the distance between two of the at least two lumens 12, 14at a distal section or end 20 of the catheter 10 can be varied. Whilethe invention is described herein in conjunction with the preferred andillustrative embodiments, it will be understood that the invention isnot limited to these embodiments.

[0024] Catheter 10 comprising multiple lumens 12, 14 can be constructedin accordance with the illustrative embodiments of the present inventionas shown in FIGS. 1-6. FIG. 1 is a perspective view of catheter 10showing the general structure of the one illustrative embodiment in anunstressed configuration. FIG. 2 is a perspective view of a distalsection 20 of the embodiment of shown in FIG. 1 showing generally thejoinable lumens configuration. FIG. 3 is a perspective view of a distalsection 20 of another illustrative embodiment showing one means forproviding the joinable lumens configuration. FIG. 4 is a perspectiveview of a distal end 20 of the embodiment another illustrativeembodiment showing another means for providing the joinable lumensconfiguration. FIG. 5 is a cross-section of the embodiment shown in FIG.1 along line 5-5′. FIG. 6 is a sectional view of the embodiment shown inFIG. 1 within the body of a patient.

[0025] Catheter 10 is intended for use in applications in which bodilyfluids, medicated solutions, and other solutions are introduced into andremoved from the body. For example, in the case of hemodialysistreatment, one embodiment of the invention is useful for the removal ofblood from a patient's blood vessel for purification and forreintroducing the blood into the patient after purification through thesame blood vessel. In such applications, catheter 10 can be used in manyblood vessels including the femoral blood vessels, subclavian bloodvessels or other blood vessels.

[0026] Referring now to FIGS. 1 and 6, catheter 10 has two ends withdistinctive functions. More particularly, a distal end 20 of catheter 10is adapted to extend within a blood vessel 44 of a patient and aproximal end 30, opposite the distal end 20, of catheter 10 is adaptedto remain outside the patient's body for cooperating with a means forexchanging fluids drawn from the blood vessel 44. Preferable, the atleast two lumens 12, 14 are approximately parallel to one another andare long enough to extend though the subcutaneous tunnel 46 from theexit site to the catheterized blood vessel 44.

[0027] The at least two lumens 12,14 are formed from two independenttubular structures. Each tubular structure has a relatively constantwall thickness and flow cross-section across its length and is used forfacilitating simultaneous opposing fluid flow between the patient and anexterior unit, for example a hemodialysis unit, and back to the patient.Each of the at least two lumens 12, 14 is preferably constructed of amaterial of a sufficient rigidity to maintain its general shape undernormal usage, including instances when negative pressure is applied tocatheter 10 (for example when aspirating blood from blood vessel 44) orwhen positive pressure is applied to the catheter 10 (for example whenintroducing blood to the blood vessel 44). Preferably, as catheter 10can be within the patient for a significant period of time, each of theat least two lumens 12, 14 also is sufficiently flexible to avoiddiscomfort, trauma, or stenosis to the patient.

[0028] As shown in FIG. 2, the at least two lumens 12, 14 of catheter 10are joinable to each other at at least one position along a regiontowards the distal end 20 of catheter 10. Preferably, the at least twolumens 12, 14 are joinable at pre-selected points generally along thefacing flat walls 34 of each of the at least two lumens 12, 14 throughjoining at least one connecting means 40. The joining of more portionsof the at least two lumens 12, 14 will decrease distance D between thetips 16, 18 of the at least two lumens 12, 14, as well as the separatedlength L between the separated lumens 12, 14.

[0029] The joining of the at least two lumens 12, 14 at at least oneposition allows the practitioner to control the distance D between, andthe length L of separation of, the at least two lumens 12, 14 at thedistal end 20. For example, if the practitioner needs the tips 16, 18 atthe distal end 20 of at least two lumens 12, 14 to be closer, thepractitioner can join more sections along the walls 34 of the at leasttwo lumens 12, 14 by using connecting means 40. Contrastingly, if thepractitioner wants to maintain an increased distance D and/or length Lat the distal end 20 between the at least two lumens 12, 14, thepractitioner will not join as many sections of the least two lumens 12,14. Preferably, once the at least two lumens 12, 14 are joined, thelumens cannot be separated without applying an undue force and/ordestroying the structural integrity of the lumens 12, 14. In thismanner, the practitioner generally can be assured that the lumens willnot separate within the patient's body.

[0030] There can be any number of connecting means 40 located along thefacing walls 34 of the at least two lumens 12, 14. However, for ease ofuse, and to decrease the number of possible clotting or coagulationsites, the use of one or two connecting means 40 is preferred. Five suchconnecting means 40 are shown in FIG. 2 that allow the joining of the atleast two lumens 12, 14 at several different lengths L. Specifically,joining connecting means 40A results in a lumen separation distance ofL1, joining connecting means 40B results in a lumen separation distanceof L2, joining connecting means 40C results in a lumen separationdistance L3, joining connecting means 40D results in a lumen separationdistance of L4, joining connecting means 40E results in a lumenseparation distance of L5, and so on. Generally, if an outer connectingmeans such as, for example, connecting means 40C is joined, allintervening connecting means 40 such as connecting means 40B and 40Aalso are joined.

[0031] Referring to FIG. 3A-3B, in one embodiment the at least twolumens 12,14 are joinable by connecting means 40 that can be a series ofinterlocking junctions. In this embodiment, the elements of eachinterlocking junction cooperate with each other to lock sections of theat least two lumens 12, 14 together. More particularly, as interlockingjunctions can have one male element 51 and one female element 52, thepractitioner can selectively join or snap sections of the at least twolumens 12, 14 together using male element 51 and female element 52.Preferably, once each of the connecting means 40 is locked together,male element 51 and female element 52 cannot be separated withoutapplying an undue or destructive force to the at least two lumens 12,14, as discussed previously, to help prevent undesirable separation ofthe lumens 12, 14.

[0032] Referring to FIG. 4, another embodiment of connecting means 40 isthrough the use of adhesive 54. Such adhesive 54 can be a natural orsynthetic adhesive. In this embodiment, the adhesive 54 preferably isprepositioned at certain intervals along at least one of the walls 34 ofthe at least two lumens 12, 14 and the practitioner uses the adhesive 54to join the lumens 12, 14. Alternatively, the adhesive 54 can be alongthe entire wall 34 of at least one or two of the at least two lumens 12,14, such that the adhesive 54 on one wall 34 interacts with the adhesive54 on another wall 34, creating a tighter bond.

[0033] Other alternatives can be used. For example, a lockingzipper-type seal, such as a variation on the zipper on plastic storagebags, can be used. One of ordinary skill in the medical device sealingfield can substitute various different locking means for the disclosedmeans without undue experimentation.

[0034] As shown in FIG. 5, the at least two lumens 12, 14 eachpreferably have an approximately semi-circular or “D”-shaped crosssection. The connecting means 40 does not affect the cross sectionalshape or interior dimensions or flow pattern of the at least two lumens12, 14. More specifically, as is known in the catheter art, each lumenhas an outer peripheral surface wall 36 defining the interior flowcavity 38. When using two lumens, as shown as the illustrative examplein the FIGs., as the lumens 12, 14 generally run parallel to each other,the generally flatter side surface walls 34 are close to and facing oneanother. The connecting means 40 preferably are located on the flatterside surface walls 34 of each lumen 12, 14. As shown, the connectingmeans 40 does not impact the size or shape of the at least two lumens12, 14.

[0035] It is understood that the generally semi-circular cross sectionis for illustrative purposes. For example, the cross section of catheter10 can be shaped as an oval, ellipse, square, triangle, kidney bean, orother shapes. Further, it should be understood that the lumens may befurther subdivided and/or additional catheter tubes of the same orvaried cross sectional configurations can be provided within the scopeof the invention. A person of ordinary skill in the art can select andconfigure catheter 10 with such shapes without undue experimentation.

[0036] Referring back to FIG. 1, the at least two lumens 12, 14 can beseparate or independent from each other starting at many differentpoints. As shown in FIG. 1, the two lumens 12, 14 shown are part of agenerally unitary double lumen structure for approximately half theirtotal length, or until splitting point S. Splitting point S can be atany selected distance from connecting hub 50, but preferably should beat a maximum distance so as to allow lumens 12, 14 to be separate andindependent from each other for a medically appropriate distance. Forexample, the medically appropriate distance for a hemodialysis cathetercan be the maximum desirable distance for use in a human being in the90%+size range. As such, the separated lumens 12, 14 could be used as isfor larger patients (those in the 90%+size range), and the joined lumens12, 14 could be used for smaller patients. Alternatively, splittingpoint S can be at the point the lumens 12, 14 leave the connecting hub50, meaning that lumens 12; 14 are separate and independent along theirentire lengths from connecting hub 50.

[0037] As shown, the independence of the at least two lumens 12, 14 canconfer several benefits to catheter 10. The distinct surface walls 34 ofeach of the at least two lumens 12, 14 can add structural stability tocatheter 10. Further, as the at least two lumens 12, 14 have individualwalls, it is possible to have separate lumens 12, 14 and thus create thesplit tipped structure of catheter 10. Importantly, the at least twolumens 12, 14 are in a free-floating configuration in the same vessel toprovide higher flow rates with lower pressures and with less occlusion.The ability to change the length L of the separation and, as a result,the separation distance D, allows the use of the same catheter 10 inmany different sized patients.

[0038] Referring now to FIG. 6, the joinable tip structure of catheter10 allows the at least two lumens 12, 14 to be spaced apart from oneanother without compromising the structure of each of the at least twolumens 12, 14. This ability to change the separation distance D andlength L between the at least two lumens 12, 14 allows the practitionerto adjust catheter 10 to fit different patients. In a hemodialysisapplication, this spacing can help to prevent mixing of cleansed bloodreturning through one of the at least two lumens with the blood beingremoved from the blood vessel through another one of the at least twolumens.

[0039] Generally, larger distances D and lengths L allow for less mixingof fluids being returned with fluids being removed. However, differentpatients have different lengths of usable blood vessels. For example, a6′10″ male patient typically would have a longer usable blood vesselthan a 4″8″ female patient. The joinable feature of the presentinvention allows the practitioner to compensate for such a difference.

[0040] In addition to the joinable lumens, catheter 10 can have many ofthe features present on conventional catheters. For example, referringback to FIG. 1, catheter 10 can have a radioplaque stripe 22 for aidingin the locating of catheter 10 by a fluoroscope. For another example,catheter 10 can have a fabric cuff 24 that is spaced accordingly toallow for optimal and/or long-term stabilization of catheter 10 in itsindwelling position. For another example, catheter 10 can have pair ofclamps 26 that can be used to secure or close off such connector tubesbefore and after a procedure. Other features for optimal utilization ofcatheter 10 are known to those with skill in the art and can be placedon catheter 10 without undue experimentation.

[0041] The proximal ends 30 of the at least two lumens 12,14 can besecured to a connecting hub 50. The connecting hub 50 couples thetubular structures of the at least two lumens 12,14 to external portions12A, 14A of lumens 12, 14 and for communicating therewith. Theconnecting hub 50 can have a suturing slot 60 that can be rotatablyanchored to the connecting hub 50. Such a suturing slot 60 may provide ameans for stabilizing the connecting hub 50 to the patient's skinadjacent the exit site.

[0042] In operation and use, catheter 10 can be used for the removal offluid to be purified from and/or subsequently for the reintroduction ofpurified fluid into patient. Before, after or during the installation ofcatheter 10, the practitioner can join the at least two lumens 12,14along the walls 34 of the at least two lumens 12, 14 using connectingmeans 40. In one embodiment, after the joining of the at least twolumens 12,14 as necessary at the appropriate point, the catheter 10 canbe installed into a patient by ordinary medical techniques, after whichcatheter 10 can perform its function. For example, in the case ofhemodialysis, after catheter 10 has been inserted through the patient'sskin into the appropriate blood vessel 44 (by techniques such as theSeldinger technique), blood can flow out of the patient through onelumen of the at least two lumens 12,14 to a purification machine andafter purification, the blood can be channeled back into the patientthrough another of the two lumens 12, 14 of catheter 10.

[0043] Each of the at least two lumens 12, 14 can be manufactured tohave a length and width useful for catheterization of an intended bloodvessel 44 and/or application. As shown, the lumens 12, 14 can belongitudinally spaced by a sufficient distance so to essentially preventor reduce the chance for the mixing of the blood to be removed and theblood to be reintroduced. The optimal distance will vary for differentapplications and with the patient that will be catheterized. One ofordinary skill in the art can manufacture catheter 10 without undueexperimentation.

[0044] The at least two lumens 12, 14 are made from a material ormaterials that such is or are flexible, durable, soft, and easilyconformable to the shape of the area to be catheterized and/or thesubcutaneous area, and that minimize risk of harm to vessel 44 walls. Ifcatheter 10 is used for hemodialysis applications, it preferably isformed of a softer material that has a hardness of at most about 85-A ona Shore durometer scale.

[0045] The at least two lumens 12, 14 can be made of biocompatibleplastics and elastomers. Such biocompatible plastics include materialssuch as, for example, polyethylene, homopolymers and copolymers of vinylacetate such as ethylene vinyl acetate copolymer, polyvinylchlorides,homopolymers and copolymers of acrylates such as polymethylmethacrylate,polyethylmethacrylate, polymethacrylate, ethylene glycol dimethacrylate,ethylene dimethacrylate and hydroxymethyl methacrylate, polyurethanes,polyvinylpyrrolidone, 2-pyrrolidone, polyacrylonitrile butadiene,polycarbonates, polyamides, fluoropolymers such as homopolymers andcopolymers of polytetrafluoroethylene and polyvinyl fluoride,polystyrenes, homopolymers and copolymers of styrene acrylonitrile,cellulose acetate, homopolymers and copolymers of acrylonitrilebutadiene styrene, polymethylpentene, polysulfones, polyesters,polyimides, polyisobutylene, polymethylstyrene and other similarcompounds known to those of ordinary skilled in the art. Suchbiocompatible elastomers include medical grade silicone rubbers,polyvinyl chloride elastomers, polyolefin homopolymeric and copolymericelastomers, urethane-based elastomers, and natural rubber or othersynthetic rubbers. One of ordinary skill in the art can select abiocompatible material suitable for manufacturing catheter 10 withoutundue experimentation.

[0046] Although embodiments of the present invention are generallydisclosed in the context of hemodialysis catheters, it is understoodthat such embodiments can be applied to other catheters that are usedfor procedures that require that fluid, blood, medicated solutions, orother solutions to be removed from and introduced into a patient. Suchprocedures include, but are not limited to, hemodialysis, perfusion,chemotherapy, and plasmapheresis.

[0047] The above detailed description of the preferred embodiments,examples, and the appended figures are for illustrative purposes onlyand are not intended to limit the scope and spirit of the invention, andits equivalents, as defined by the appended claims. One skilled in theart will recognize that many variations can be made to the inventiondisclosed in this specification without departing from the scope andspirit of the invention

What is claimed is:
 1. A multiple lumen catheter comprising: a. a first lumen having a proximal end and a distal end; b. a second lumen having a proximal end and a distal end, c. a connecting means for selectively and irreversibly joining together at least a portion of the distal ends of the first and second lumens; wherein the first lumen and the second lumen are generally parallel; a connecting hub connects the proximal ends of the first and the second lumens; and a first fluid flow in the first lumen is in a direction different from a second fluid flow in the second lumen.
 2. The catheter as claimed in claim 1, wherein the catheter is not split at predetermined distances from the distal end of the first or the second lumen.
 3. The catheter claimed in claim 2, wherein the first lumen and the second lumen are selectively joinable at at least one position along the generally flat side surfaces.
 4. The catheter claimed in claim 3, wherein the selective joining of the first and second lumens decreases the distance between the first and second lumens proximal to the distal ends of the first and second lumens.
 5. The catheter claimed in claim 4, wherein the first lumen and the second lumen each have a generally semi-circular cross section and each comprise at least one generally flat side surface.
 6. The catheter claimed in claim 5, wherein the connecting means is at least one lockable junction comprising a male end and female end, wherein once the at least one lockable junction is joined together it is joined irreversibly; whereby the first lumen and the second lumen are joined selectively along a portion of the distal ends of the first lumen and the second lumen through the joining of the male end with female end.
 7. The catheter claimed in claim 5, wherein the first lumen and the second lumen are joinable by an adhesive.
 8. The catheter claimed in claim 4 further comprising a third lumen.
 9. A multiple lumen catheter comprising: a. a first lumen having a proximal end and a distal end; b. a second lumen having a proximal end and a distal end; c. a connecting means for selectively and irreversibly joining together at least a portion of the distal ends of the first and second lumens; wherein a connecting hub connects the first and the second lumens at the proximal ends; a first fluid flow in the first lumen is in a direction different from a second fluid flow of the second lumen; the connecting means allows the first lumen and the second lumen to be selectively joined together at the discretion of a practitioner at a position proximal to the distal ends of the first and second lumens; whereby the selective joining of the first and second lumens decreases the distance between the first and second lumens proximal to the distal ends of the first and second lumens.
 10. The catheter as claimed in claim 9, wherein the first lumen and the second lumen are approximately parallel.
 11. The catheter as claimed in claim 10, wherein the distal end of the first lumen is longer than the distal end of the second lumen.
 12. The catheter as claimed in claim 11, wherein the distal end of the first lumen extends beyond the distal end of the second lumen within a patient and the first lumen is for introducing a fluid into a blood vessel in the patient and the second lumen is for removing a fluid from the blood vessel.
 13. The catheter as claimed in claim 12, wherein the connecting means is at least one lockable junction comprising a male end and female end, wherein once the at least one lockable junction is joined together it is joined irreversibly; whereby the first and second lumens are joined selectively along a portion of the distal ends of the first and second lumens through the joining of the male end with female end.
 14. The catheter claimed in claim 12, wherein the first lumen and the second lumen are joinable by an adhesive.
 15. The catheter as claimed in claim 13, wherein the first and second lumens cannot be joined beyond a preselected point set between the proximal end and the distal end of each of the first and second lumens.
 16. The catheter as claimed in claim 15, wherein the set point is at the distal end of the first lumen.
 17. The catheter as claimed in claim 16, wherein the catheter is a hemodialysis catheter.
 18. A multiple lumen catheter, comprising: a. a first lumen defined by a first outer wall and having a proximal end and a distal end; b. a second lumen defined by a second outer wall and having a proximal end and a distal end; wherein a connecting hub connects the first lumen and the second lumen at the proximal ends; a first fluid flow in the first lumen is in a direction different from a second fluid flow in the second lumen; the first lumen and the second lumen are joinable at at least one point along the first outer wall and the second outer wall by a connecting means; the connecting means allows the first lumen and the second lumen to be selectively joined at the discretion of a practitioner; whereby the selectively joining of the first lumen and the second lumen decreases the separation distance between the first lumen and the second lumen proximal to the distal ends of the first lumen and the second lumen.
 19. The catheter as claimed in claim 18, wherein the connecting means is at least one lockable junction comprising a male end and female end, wherein once the at least one lockable junction is joined together it is joined irreversibly; whereby the first lumen and the second lumen are joined selectively along a portion of the distal ends of the first lumen and the second lumen through the joining of the male end with female end.
 20. The catheter as claimed in claim 18, wherein the joining means is an adhesive on the outer wall of at least one of the lumens.
 21. The catheter as claimed in claim 18, wherein the first lumen and the second lumen cannot be joined beyond a preselected point set between the proximal end and the distal end of each of the first and second lumens.
 22. The catheter as claimed in claim 21, wherein the set point is at the distal end of the first lumen.
 23. The catheter as claimed in claim 21, wherein the catheter is a hemodialysis catheter. 